1. Field of the Invention
The present invention relates to vegetable oil compositions and in particular to those vegetable oil compositions which are edible.
2. Introduction to the Invention
The present invention deals with a manner of stabilizing vegetable oils against oxidation. The invention in particularly deals with high oleic oils which are believed to be more healthy for the diet. In particular, high oleic content vegetable oils are believed to reduce low density lipoprotein cholesterol. Low density lipoprotein cholesterol has been referred in the literature as "bad cholesterol" which is that believed responsible for plaque buildup on the walls of blood vessels.
The use of high oleic vegetable oils has been of further interest in the diet in recent years in that it is also believed that a high saturated fat content in the diet may also lead to the formation of plaque. Thus the present invention provides a benefit in giving an oxidatively stable oil in which two distinct mechanisms are believed to reduce cholesterol.
It is noted that saturated fats are more stable than unsaturated fats because of the absence of a double bond in saturated fats. Of course, as the oils of the present invention are high in oleic content they correspondingly contain a high degree of mono-unsaturation in the oil.
The higher the degree of unsaturation in an oil the more likely that the oil will go rancid (oxidize). It is particularly critical in dietary oils which are used for frying, such as French frying, that the oil be stable for a long period of time. Many fast food manufacturers have utilized saturated fats, and in particular saturated animal fats, because of their ability to withstand long periods of time at elevated temperatures in the manufacture of fried foods. Of course, as the fried food absorbs the saturated fat such is taken into the human diet. Thus while a saturated fat may be oxidatively stable for frying it is unfortunate that a dietary component with the problems previously addressed are encountered.
Many antioxidants present problems especially when used at high levels in industrial applications. The tocopherol antioxidants are environmentally friendly and compliment the natural oils described herein.
Thus it remains to develop a vegetable oil which is high in oleic acid content, and low in saturates or polyunsaturated oils which is oxidatively stable and which may be utilized for deep frying. Other uses of oils include crankcase, gear lubricants, transmission oils, tractor oils and hydraulic fluids.
It is known from U.S. Pat. No. 2,267,224 issued Dec. 23, 1941 to Taylor et al that lard shortening may be stabilized through the use of tocopherol at levels of 0.02% to 0.06%. The present invention does not deal with lard which contains large amounts of cholesterol (which should be avoided in the diet), and the oil of the invention does not contain the high degree of saturates or linoleic acid moieties which are found in lard. It is further noted that the compositions of Taylor et al are suggested for use in hydrogenated lard. In fact it is noted that the tocopherol is also hydrogenated in Taylor et al.
Hickman in U.S. Pat. No. 2,349,277 issued May 23, 1944 suggests a method of preparing a deodorized relatively stable edible triglyceride. Jacobsen in U.S. Pat. No. 2,363,672 issued Nov. 7, 1941 suggests that animal and vegetable shortenings may be treated by adding a tocopherol-containing deodorizer sludge to shortening and hydrogenating the resultant mixture.
U.S. Pat. No. 2,440,606 issued Apr. 27, 1948 to Hickman suggests methods for obtaining tocopherol or vitamin E produced during the vacuum-inert gas deodorization treatment of vegetable or animal oils. Mattill et al in U.S. Pat. No. 2,333,655 issued Nov. 9, 1943 describes obtaining the use of beta-tocopherol in lard. Similar disclosures are also found in U.S. Pat. Nos. 2,333,656 and 2,333,657 both issued to Mattill et al on Nov. 9, 1943.
Golub in U.S. Pat. No. 3,117,866 issued Jan. 14, 1964 discusses the use of phosphatides, oils, and tocopherol at levels of 0.25% to 2% in an oleaginous composition. Klaui et al in U.S. Pat. No. 3,637,772 issued Jan. 25, 1972 suggests the use of tocopherols in combination with colamine or its salt, and a higher fatty acid ester of ascorbic acid. Nelan in U.S. Pat. No. 3,173,927 issued Mar. 16, 1975 discusses various methods for obtaining tocopherol.
High oleic vegetable oils with which the present is concerned may be obtained from any one of several sources. The first and most important source of high oleic acid content vegetable oils are described in Fick's U.S. Pat. Nos. 4,627,192 and 4,743,402 issued respectively Dec. 9, 1986 and May 10, 1988. The Fick patents describe obtaining in large quantities high oleic vegetable oils having greater than 80% oleic acid. The Fick oils are also noted for their high degree of stability with regard to the AOM values as hereinafter described.
It is also known from European Patent Application 88 312397.8 filed Dec. 29, 1988 that high oleic content rapeseed (canola) may be used as a source of a high oleic content vegetable oil. Low saturated fat content oils are described in U.S. Pat. No. 4,948,811 issued Aug. 14, 1990 to Spinner et al.
The vegetable oil products of the present invention provide highly stable oils for cooking which have the desirable benefits of low saturate and low linoleic acid levels while maintaining a relatively high degree of mono-unsaturate in the oil.
To the extent that any of the foregoing references are applicable they are herein explicitly incorporated by reference. Temperatures and pressures given herein are in degrees C and KPa absolute unless otherwise indicated. When discussing the fatty acid content of a triglyceride oil such relates to the average molar amount of the fatty acid species which make up the triglyceride. Ranges and ratios given herein may be combined.